1. Field of the Invention
This invention relates generally to traffic information for drivers, and more particularly to a method and system for providing dynamic information useful on a real time basis for roadway travelers.
2. Discussion of the Related Art
Traffic control and acquisition of traffic information have become indispensable because of the growing volume of traffic. Normally the prevailing dynamic traffic information may be acquired by:
fixed built-on accessories on roads, such as induction loops, cameras, emergency call boxes; PA1 traffic counters or traffic detectors; PA1 mobile traffic units, such as police, road service, helicopter; PA1 weather information collecting systems; and a multitude of other information sources not mentioned here.
Disadvantages of the previous methods of obtaining traffic information include the great amount of personnel and materials required, the high cost associated with these methods, and the very long "reaction times" for some events such as accidents, congestion or weather-related traffic problems. Due to the enormous expense, complete coverage of an area in acquisition of traffic information based on sensors in the streets is virtually impossible, so that main areas of emphasis must always be established in data acquisition.
In addition, such a decentralized acquisition of traffic information presents problems when the information is to be compiled and processed centrally and relayed to third parties, such as police, road service personnel, and traffic participants.
German patent 4,105,584 discloses a traffic information system that works on the basis of a mobile communication system. Traffic information is transmitted from a central office to vehicles over an organization channel of the mobile communication system, where the information thus transmitted can be displayed visually and/or acoustically in the vehicle. In addition, means are provided for obtaining information regarding the location and/or movement of the vehicle and sending it to the central office. If a cellular mobile communication system is used, an approximate tracking of a vehicle on the basis of its position in a certain wireless cell is possible.